EASY
AS and A Level
IMPORTANT
Earn 100

There are eight letters in a post box, and five of them are addressed to Mr Nut. Mr Nut removes four letters at random from the box.

Draw up the probability distribution table for N, the number of selected letters that are addressed to Mr Nut.

Important Questions on Probability Distributions

EASY
AS and A Level
IMPORTANT

There are eight letters in a post box, and five of them are addressed to Mr Nut. Mr Nut removes four letters at random from the box.

Describe one significant feature of a vertical line graph or bar chart that could be used to represent the probability distribution for N.

EASY
AS and A Level
IMPORTANT
A discrete random variable Y is such that Y8, 9, 10. Given that PY=y=ky, find the value of the constant k.
EASY
AS and A Level
IMPORTANT

θ is a discrete random variable and θ3, 4, 5, 6. Given that Pθ=q=cq2 find the value of the constant c.

EASY
AS and A Level
IMPORTANT

θ is a discrete random variable and θ3, 4, 5, 6. Hence, find Pθ>4.

EASY
AS and A Level
IMPORTANT

Four books are randomly selected from a box containing 10 novels, 10 reference books and 5 dictionaries. The random variable N represents the number of novels selected.

Find the value of PN=2, correct to 3 significant figures.

EASY
AS and A Level
IMPORTANT

Four books are randomly selected from a box containing 10 novels, 10 reference books and 5 dictionaries. The random variable N represents the number of novels selected.

Without further calculation, state which of N=0 or N=4 is more likely. Explain the reasons for your answer.

EASY
AS and A Level
IMPORTANT

In a game, a fair 4-sided spinner with edges labelled 0,1,2 and 3 is spun. If a player spins 1,2 or 3, then that is their score. If a player scores 0, then they spin a fair triangular spinner with edges labelled 0,1 and 2, and the number they spin is their score. Let the variable X represent a player's score.

Show that PX=0=112.

EASY
AS and A Level
IMPORTANT

In a game, a fair 4-sided spinner with edges labelled 0,1,2 and 3 is spun. If a player spins 1,2 or 3, then that is their score. If a player scores 0, then they spin a fair triangular spinner with edges labelled 0,1 and 2, and the number they spin is their score. Let the variable X represent a player's score.

Draw up the probability distribution table for X, and find the probability that X is a prime number.